The present invention relates generally to an emergency-lock-type safety or seat belt retractor for an automotive vehicle, which includes a mechanism facilitating release of the lock-up condition of the retractor. More specifically, the invention relates to an emergency lock safety belt retractor having a lock-up release mechanism which can release the retractor even when the webbing is fully retracted.
In general, an emergency-lock-type safety belt retractor is provided with a sensor which detects abnormally abrupt deceleration of the vehicle to lock a belt spool about which a webbing is wound, and a second sensor which detects abnormally abrupt movement of the webbing out of the belt spool. The locking action mediated by the second sensor can normally be released by retracting the webbing slightly. The sensor detecting abrupt vehicle deceleration will be hereafter referred to as "vehicle sensor". On the other hand, the sensor detecting abrupt movement of the webbing will be hereafter referred to as "webbing sensor".
The webbing sensor may lock the retractor after the webbing is fully retracted on the spool due to a characteristic abrupt deceleration at the end of the retraction stroke. This state in which the retractor becomes locked after full retraction of the webbing will be hereafter referred to as "lock-up state". If the retractor falls into lock-up state after the belt has been fully retracted, releasing the retractor from the lock-up state is problematic as there is no leeway for further retraction.